CardInputWidget.CardValidCallback will consider the postal code in validation.

example/src/main/java/com/stripe/example/activity/CreateCardSourceActivity.kt

@@ -2,6 +2,7 @@ package com.stripe.example.activity
 
 import android.content.Intent
 import android.os.Bundle
+import android.util.Log
 import android.view.View
 import androidx.activity.viewModels
 import androidx.appcompat.app.AlertDialog
@@ -50,11 +51,21 @@ class CreateCardSourceActivity : AppCompatActivity() {
         setContentView(viewBinding.root)
 
         viewBinding.createButton.setOnClickListener {
+            // If a field is invalid this will shift focus to that field
             viewBinding.cardWidget.cardParams?.let {
                 createCardSource(it)
             } ?: showSnackbar("Enter a valid card.")
         }
 
+        viewBinding.cardWidget.setCardValidCallback { isValid, invalidFields -> // We will not call cardParams unless it is valid because
+            // this will cause the inFocus field to change.
+            if (isValid) {
+                Log.e("STRIPE", "Validity: $isValid, ${viewBinding.cardWidget.cardParams}")
+            } else {
+                Log.e("STRIPE", "Validity: $isValid, invalidField: $invalidFields")
+            }
+        }
+
         viewBinding.recyclerView.setHasFixedSize(true)
         viewBinding.recyclerView.layoutManager = LinearLayoutManager(this)
         viewBinding.recyclerView.adapter = sourcesAdapter

payments-core/src/main/java/com/stripe/android/view/CardInputWidget.kt

@@ -106,6 +106,9 @@ class CardInputWidget @JvmOverloads constructor(
                 },
                 CardValidCallback.Fields.Cvc.takeIf {
                     this.cvc == null
+                },
+                CardValidCallback.Fields.Postal.takeIf {
+                    isPostalRequired() && postalCodeEditText.postalCode.isNullOrBlank()
                 }
             ).toSet()
         }
@@ -152,8 +155,8 @@ class CardInputWidget @JvmOverloads constructor(
 
     @VisibleForTesting
     @JvmSynthetic
-    internal val requiredFields: List<StripeEditText>
-    private val allFields: List<StripeEditText>
+    internal val requiredFields: MutableSet<StripeEditText>
+    private val allFields: Set<StripeEditText>
 
     /**
      * The [StripeEditText] fields that are currently enabled and active in the UI.
@@ -169,7 +172,7 @@ class CardInputWidget @JvmOverloads constructor(
 
     /**
      * A [PaymentMethodCreateParams.Card] representing the card details if all fields are valid;
-     * otherwise `null`
+     * otherwise `null`. If a field is invalid focus will shift to the invalid field.
      */
     override val paymentMethodCard: PaymentMethodCreateParams.Card?
         get() {
@@ -197,7 +200,7 @@ class CardInputWidget @JvmOverloads constructor(
 
     /**
      * A [PaymentMethodCreateParams] representing the card details and postal code if all fields
-     * are valid; otherwise `null`
+     * are valid; otherwise `null`. If a field is invalid focus will shift to the invalid field
      */
     override val paymentMethodCreateParams: PaymentMethodCreateParams?
         get() {
@@ -208,7 +211,7 @@ class CardInputWidget @JvmOverloads constructor(
 
     /**
      * A [CardParams] representing the card details and postal code if all fields are valid;
-     * otherwise `null`
+     * otherwise `null`. If a field is invalid focus will shift to the invalid field.
      */
     override val cardParams: CardParams?
         get() {
@@ -275,7 +278,7 @@ class CardInputWidget @JvmOverloads constructor(
     /**
      * The postal code field is enabled by default. Disabling the postal code field may impact
      * auth success rates, so it is discouraged to disable it unless you are collecting the postal
-     * code outside of this form.
+     * code outside of this form.  If the postal code is disabled it will not be shown in the view.
      */
     var postalCodeEnabled: Boolean by Delegates.observable(
         CardWidget.DEFAULT_POSTAL_CODE_ENABLED
@@ -291,6 +294,7 @@ class CardInputWidget @JvmOverloads constructor(
 
             cvcEditText.imeOptions = EditorInfo.IME_ACTION_DONE
         }
+        updatePostalRequired()
     }
 
     /**
@@ -302,7 +306,11 @@ class CardInputWidget @JvmOverloads constructor(
      * Note that some countries do not have postal codes, so requiring postal code will prevent
      * those users from submitting this form successfully.
      */
-    var postalCodeRequired: Boolean = CardWidget.DEFAULT_POSTAL_CODE_REQUIRED
+    var postalCodeRequired: Boolean by Delegates.observable(
+        CardWidget.DEFAULT_POSTAL_CODE_REQUIRED
+    ) { _, _, _ ->
+        updatePostalRequired()
+    }
 
     /**
      * If [postalCodeEnabled] is true and [usZipCodeRequired] is true, then postal code is a
@@ -318,8 +326,20 @@ class CardInputWidget @JvmOverloads constructor(
         } else {
             postalCodeEditText.config = PostalCodeEditText.Config.Global
         }
+
+        updatePostalRequired()
+    }
+
+    private fun updatePostalRequired() {
+        if (isPostalRequired()) {
+            requiredFields.add(postalCodeEditText)
+        } else {
+            requiredFields.remove(postalCodeEditText)
+        }
     }
 
+    private fun isPostalRequired() = (postalCodeRequired || usZipCodeRequired) && postalCodeEnabled
+
     private val frameStart: Int
         get() {
             val isLtr = context.resources.configuration.layoutDirection == View.LAYOUT_DIRECTION_LTR
@@ -342,7 +362,7 @@ class CardInputWidget @JvmOverloads constructor(
 
         frameWidthSupplier = { containerLayout.width }
 
-        requiredFields = listOf(
+        requiredFields = mutableSetOf(
             cardNumberEditText,
             cvcEditText,
             expiryDateEditText
@@ -481,8 +501,8 @@ class CardInputWidget @JvmOverloads constructor(
      * Override of [View.isEnabled] that returns `true` only
      * if all three sub-controls are enabled.
      *
-     * @return `true` if the card number field, expiry field, and cvc field are enabled,
-     * `false` otherwise
+     * @return `true` if the card number field, expiry field, cvc field, and postal (if required)
+     * are enabled, `false` otherwise
      */
     override fun isEnabled(): Boolean {
         return requiredFields.all { it.isEnabled }

payments-core/src/test/java/com/stripe/android/view/CardInputWidgetTest.kt

@@ -1297,18 +1297,18 @@ internal class CardInputWidgetTest {
         idleLooper()
 
         assertThat(cardInputWidget.requiredFields)
-            .isEqualTo(cardInputWidget.currentFields)
+            .isEqualTo(cardInputWidget.currentFields.toHashSet())
     }
 
     @Test
     fun currentFields_notEquals_requiredFields_withPostalCodeEnabled() {
         cardInputWidget.postalCodeEnabled = true
         assertThat(cardInputWidget.requiredFields)
-            .isNotEqualTo(cardInputWidget.currentFields)
+            .isNotEqualTo(cardInputWidget.currentFields.toHashSet())
     }
 
     @Test
-    fun testCardValidCallback() {
+    fun testCardValidCallback_withPostalCodeDefaultDisabled() {
         var currentIsValid = false
         var currentInvalidFields = emptySet<CardValidCallback.Fields>()
         cardInputWidget.setCardValidCallback { isValid, invalidFields ->
@@ -1362,6 +1362,60 @@ internal class CardInputWidgetTest {
             .containsExactly(CardValidCallback.Fields.Cvc)
     }
 
+    @Test
+    fun testCardValidCallback_withPostalCodeEnabledNotRequired() {
+        var currentIsValid = false
+        var currentInvalidFields = emptySet<CardValidCallback.Fields>()
+        cardInputWidget.postalCodeEnabled = true
+        cardInputWidget.setCardValidCallback { isValid, invalidFields ->
+            currentIsValid = isValid
+            currentInvalidFields = invalidFields
+        }
+        assertThat(currentIsValid)
+            .isFalse()
+        assertThat(currentInvalidFields)
+            .containsExactly(
+                CardValidCallback.Fields.Number,
+                CardValidCallback.Fields.Expiry,
+                CardValidCallback.Fields.Cvc
+            )
+    }
+
+    @Test
+    fun testCardValidCallback_withPostalCodeEnabledAndRequired() {
+        var currentIsValid = false
+        var currentInvalidFields = emptySet<CardValidCallback.Fields>()
+        cardInputWidget.postalCodeEnabled = true
+        cardInputWidget.usZipCodeRequired = true
+        cardInputWidget.setCardValidCallback { isValid, invalidFields ->
+            currentIsValid = isValid
+            currentInvalidFields = invalidFields
+        }
+        assertThat(currentIsValid)
+            .isFalse()
+        assertThat(currentInvalidFields)
+            .containsExactly(
+                CardValidCallback.Fields.Number,
+                CardValidCallback.Fields.Expiry,
+                CardValidCallback.Fields.Cvc,
+                CardValidCallback.Fields.Postal
+            )
+
+        cardInputWidget.setCardNumber(VISA_NO_SPACES)
+        expiryEditText.setText("1250")
+        cvcEditText.setText("123")
+        assertThat(currentIsValid).isFalse()
+        assertThat(currentInvalidFields).containsExactly(CardValidCallback.Fields.Postal)
+
+        postalCodeEditText.setText("12345")
+        assertThat(currentIsValid).isTrue()
+        assertThat(currentInvalidFields).isEmpty()
+
+        postalCodeEditText.setText("123")
+        assertThat(currentIsValid).isFalse()
+        assertThat(currentInvalidFields).containsExactly(CardValidCallback.Fields.Postal)
+    }
+
     @Test
     fun shouldShowErrorIcon_shouldBeUpdatedCorrectly() {
         cardInputWidget.setExpiryDate(12, 2030)
@@ -1480,31 +1534,35 @@ internal class CardInputWidgetTest {
 
     @Test
     fun `Verify on postal code focus change listeners trigger the callback`() {
-        cardInputWidget.postalCodeEditText.getParentOnFocusChangeListener().onFocusChange(cardInputWidget.postalCodeEditText, true)
+        cardInputWidget.postalCodeEditText.getParentOnFocusChangeListener()
+            .onFocusChange(cardInputWidget.postalCodeEditText, true)
 
         assertThat(cardInputListener.focusedFields)
             .contains(CardInputListener.FocusField.PostalCode)
     }
 
     @Test
     fun `Verify on cvc focus change listeners trigger the callback`() {
-        cardInputWidget.cvcEditText.getParentOnFocusChangeListener().onFocusChange(cardInputWidget.cvcEditText, true)
+        cardInputWidget.cvcEditText.getParentOnFocusChangeListener()
+            .onFocusChange(cardInputWidget.cvcEditText, true)
 
         assertThat(cardInputListener.focusedFields)
             .contains(CardInputListener.FocusField.Cvc)
     }
 
     @Test
     fun `Verify on expiration date focus change listeners trigger the callback`() {
-        cardInputWidget.expiryDateEditText.getParentOnFocusChangeListener().onFocusChange(cardInputWidget.expiryDateEditText, true)
+        cardInputWidget.expiryDateEditText.getParentOnFocusChangeListener()
+            .onFocusChange(cardInputWidget.expiryDateEditText, true)
 
         assertThat(cardInputListener.focusedFields)
             .contains(CardInputListener.FocusField.ExpiryDate)
     }
 
     @Test
     fun `Verify on card number focus change listeners trigger the callback`() {
-        cardInputWidget.cardNumberEditText.getParentOnFocusChangeListener().onFocusChange(cardInputWidget.cardNumberEditText, true)
+        cardInputWidget.cardNumberEditText.getParentOnFocusChangeListener()
+            .onFocusChange(cardInputWidget.cardNumberEditText, true)
 
         assertThat(cardInputListener.focusedFields)
             .contains(CardInputListener.FocusField.CardNumber)